Linear ball bearings of said type are known for the mounting of machine parts which can move back and forth. Such machine parts include, for example, a drive spindle and a bearing housing of a machine tool. The linear ball bearings have the task of ensuring low-friction mounting in the movement direction. To ensure correct functioning at least also in the event of relatively small alignment errors between the parts which move relative to one another, it is provided in special designs that the supporting race elements of the linear ball bearings have a convexity, that is to say at least one radial outer surface, which is arched or elevated outward at least in one direction, for contact against an inner surface of the part surrounding the guide rail. In this way, the supporting race elements can move in a tilting fashion on the contact surface of the part surrounding the guide rail, and alignment errors can be substantially compensated in this way.
The production of the convexity of the supporting race elements is comparatively expensive. Said convexity is generally produced by bending the supporting race elements in the desired direction. On account of the bending which has taken place, those raceways of the supporting race element which are situated opposite the convex outer surface must subsequently be ground to obtain the desired raceway quality. Hardening of the supporting race elements is sometimes also provided.
WO 01/11251 A1 (DE 199 37 278 A1) discloses a generic linear ball bearing. Said linear ball bearing has supporting race elements which have an outer surface which is arched outward in two directions and which can therefore roll very effectively, in pivoting movements, on the bore inner surface of a machine housing which surrounds the linear ball bearing. The supporting race elements are also held in housing-like holding parts which in turn are arranged, such that they can be inserted and removed in the radial direction, in recesses of a sleeve-like cage.
DE 39 10 469 A1 describes a linear ball bearing in which supporting race elements are likewise inserted in recesses of a cage. The outer surface, which is designed for rocking contact against an inner circumferential surface of a bearing housing bore which holds the cage, of the supporting race elements slopes down in the radially inward direction in relation to the cage axis from a central region, which is situated in the region of the rocking axis of said supporting race elements, toward the ends of the supporting race elements.
DE 1 949 182 A1 also discloses a linear ball bearing in which supporting race elements, which are beveled in their longitudinal direction from the center toward the ends, are inserted into recesses of a cage. The central part of the supporting race elements forms a rotational axis and thereby enables a tilting movement, as a result of which angular errors between the parts which move relative to one another can be compensated.
DE 199 54 387 A1 likewise describes a linear ball bearing for mounting a shaft, having supporting race elements whose radial outer surfaces are of arched design such that the supporting race elements can, by tilting, adjust to dimensional tolerances of the shaft.
Finally, U.S. Pat. No. 5,558,442 is mentioned, which describes a linear ball bearing having supporting race elements which, as viewed in their longitudinal extent, have in the central region of said linear ball bearing a radial outer surface which is arched in its longitudinal direction, with the arching extending over the entire width of the supporting race elements.
The invention also relates to a supporting race element for use in a linear ball bearing and to a method for producing a supporting race element of said type, and to an embossing device for producing the supporting race element.